Human Immunodeficiency Virus

Human immunodeficiency virus, or HIV, is a virus that attacks the body’s immune system  specifically, white blood cells called CD4-positive (CD4+) T-helper cells.

Those cells, which are sometimes referred to as CD4 cells, T-helper cells, or T4 cells, play an important role in identifying pathogens that invade the body and in marshaling an immune response against them. Left untreated, HIV infiltrates and destroys CD4 cells, impairing the immune system’s ability to fight off infections and diseases.
When the number of CD4 cells drops low enough, or certain infections related to an impaired immune system occur, a person may be diagnosed with the final stage of HIV infection: acquired immunodeficiency syndrome, or Human immunodeficiency virus AIDS.

When the immune system is weakened from AIDS, the body may have difficulty fighting off certain cancers or viral, fungal, or bacterial infections, and these conditions may prove fatal.

While there’s no cure for HIV yet, effective HIV treatment, known as antiretroviral therapy (ART), can reduce the amount of virus to undetectable levels, allow people to live longer, healthier lives, and help prevent the virus’s transmission to others.

Signs and Symptoms of Human immunodeficiency virus HIV/AIDS

There are three main stages of HIV infection, each with its own symptoms.

Stage 1: Acute HIV Infection

Within the first two to four weeks after HIV infection, about two-thirds of people will experience symptoms that feel like a really bad flu. As the immune system rallies to fight off the virus, fever may develop along with additional symptoms, such as sore throat, swollen glands, mouth sores, rashes, diarrhea, fatigue, headache, and muscle and joint pain.

This stage, called acute infection or primary HIV infection, can last for a few days, or it can stretch into weeks.

Stage 2: Clinical Latency

If the infection goes undiagnosed or untreated, the immune system can bring the Human immunodeficiency virus HIV level down some, but it can’t completely control or contain it; the virus is still active but multiplies more slowly, often without causing any symptoms. This is also called the clinical latency stage, or chronic Human immunodeficiency virus HIV infection, and it can last up to 15 years.

At this stage, people with HIV who aren’t taking medication still have a sufficient amount of virus in their system to transmit it to others, even if they don’t have symptoms, and the virus continues to damage the immune system over that time, leading to worsening health.

Stage 3: AIDS

If a person goes for years without treatment for HIV, the next and final stage is AIDS.

AIDS symptoms can include:
  • Sudden weight loss
  • Recurring fever
  • Night sweats
  • Fatigue and weakness
  • Swollen lymph glands
  • Chronic diarrhea
  • Sores in the mouth, anus, or genitals
  • Blotches on the skin, under the skin, or inside the mouth, nose, or eyelids
  • Neurological issues, including memory loss and depression
Some of these symptoms may be the result of a so-called opportunistic infection, such as pneumonia, which an immune system badly damaged by HIV can’t effectively fight.

Causes and Risk Factors of HIV/AIDS

HIV is spread by direct contact with certain body fluids from a person with HIV who has a detectable viral load. These fluids are:

  • Blood
  • Semen (cum) and preseminal fluid
  • Rectal fluids
  • Vaginal fluids
  • Breast milk
For transmission to occur, the virus in these fluids must enter the bloodstream of an HIV-negative person through a mucous membrane (found in the rectum, vagina, mouth, or tip of the penis), through open cuts or sores, or direct injection.

In the United States, HIV is mostly spread through sex, particularly anal and vaginal intercourse. People can also transmit HIV by sharing used injection equipment, such as syringes and other paraphernalia.

Mothers can spread HIV to babies during pregnancy, birth, and breastfeeding.
HIV is a flimsy virus that can’t live for long outside the human body and can’t reproduce without a human host. That means it isn’t spread through saliva on silverware; from kisses on the cheek, hugs, sharing toilets, or closed-mouth kissing; or by mosquitoes, ticks, and other insects.

If a person is on effective antiretroviral treatment for HIV, they can lower their viral load to an undetectable level, at which point they effectively have no risk of sexually transmitting HIV to their HIV-negative partners.

How Is HIV/AIDS Diagnosed?

Who Should Be Tested for HIV

The CDC recommends that everyone age 13 to 64 get tested for HIV at least once.

People more vulnerable to HIV should get tested more frequently. The CDC defines people in this higher-risk group as those who have:

  • Had more than one sex partner in the past year
  • Had an HIV-positive partner
  • Been diagnosed with or treated for hepatitis or tuberculosis or a sexually transmitted disease in the past year
  • Exchanged sex for drugs or money
  • Shared injection equipment
If you aren’t in any of these higher-risk groups but you think your partner may be, the CDC thinks you should be tested, too.
People who are pregnant or trying to become pregnant should also be tested. If you do have HIV, starting treatment in pregnancy can dramatically reduce the chance that your child will be born with HIV.
For men who have sex with men, the CDC recommends annual Human immunodeficiency virus HIV testing but notes that some doctors may advise a schedule of every three to six months for certain patients, depending on other risk factors.

Types of HIV Tests

There are lots of options for Human immunodeficiency virus HIV tests. There are tests that analyze saliva, blood, or even urine. Tests screen for different signs of HIV infection: antibodies (proteins your body makes to fight the virus); antigens (proteins on the surface of HIV cells that trigger the production of antibodies); or actual genetic material from the HIV virus.

Which test you take depends on how recently you think you may have been exposed to HIV, how long you want to wait for results, and how you feel about blood draws.

Nucleic acid test (NAT): 10 to 33 days after an exposure 
For people with flu-like symptoms and a recent high-risk exposure, a nucleic acid test (NAT) can detect HIV’s genetic material in the blood. This test must be taken in a clinic and is expensive. Usually, healthcare providers use it to confirm other tests.

Antibody/antigen test: 18 to 45 days after an exposure

This test, commonly performed in a lab, checks for both antibodies and antigens. Antigens are detectable in the blood before antibodies develop, signaling the presence of HIV. An antibody/antigen test can be a rapid test that uses blood from a finger prick and delivers results in less than 30 minutes. Or it could be a test that uses blood drawn from a vein and delivers results in a few days.

Antibody test: 23 to 90 days after an exposure 

An antibody-only test uses a fluid sample swabbed from inside your cheek or blood from a finger prick. These rapid tests and at-home tests can detect HIV antibodies three weeks after exposure at the earliest and deliver results in 20 to 30 minutes. They are also good at detecting chronic HIV.

There are antibody-only tests that use blood drawn from a vein rather than a finger prick. These tests can typically detect the infection sooner after exposure but take several days to deliver results, and are conducted at a lab.
All positive antibody tests should be followed up with an additional test to confirm results.

Diagnosis of AIDS

A person is diagnosed with AIDS when one of two things happen:

  • CD4 cell count drops from normal levels of 500–1,200 cells per cubic millimeter to 200 cells or fewer.As the CD4 count drops, usually the volume of Human immunodeficiency virus HIV in the blood, known as the viral load, rises.
  • Viral, fungal, or bacterial infections, and cancers, which healthy immune systems can fight off, emerge and worsen. These so-called AIDS-defining conditions are often the cause of death for people living with HIV who are not receiving treatment.

Prognosis of HIV

A positive diagnosis of HIV can be overwhelming, but effective treatment exists, and it’s important to start treatment as soon as possible. With the right medicines, people with HIV can now live longer, healthier lives with a very low risk of transmission to others.

Duration of HIV

There’s currently no cure for HIV; once you get HIV, you have it for life.But HIV medicines have dramatically improved life expectancy for people with HIV, and with the right treatment and care, someone with HIV can now have a life expectancy similar to that of an HIV-negative person.
If HIV is left untreated, signs of illness can develop within 5 to 10 years and the time span from HIV transmission to a diagnosis of AIDS is about 10 to 15 years.

Treatment and Medication Options for HIV

If you test positive for HIV, research shows that if you start taking medicine immediately (or even return to treatment after some time off) and stay on it, you can bring the amount of virus in your blood (your viral load) to undetectable levels, protect your immune system, and prevent transmission to others.
Agencies such as the National Institutes of Health (NIH) recommend you start HIV treatment as soon as possible after diagnosis.
Talk to a healthcare provider about treatment choices and the resources that are available to you.There are no-fee or low-cost programs that ensure that everyone, no matter their income or insurance status, can receive and stay on treatment.

Medication Option

There are more than 30 different HIV drugs, divided into eight classes. Known collectively as antiretroviral therapy (ART), they prevent the virus from replicating in different ways. People typically take a combination of three drugs from at least two different classes, although new drug combinations require only two medicines, combined in one pill.
Most antiretroviral drugs need to be taken every day to work properly. Although it can be difficult to stick to this routine, it’s a must in order to keep your viral load (the amount of HIV in your body) low and avoid developing possible drug resistance.
In January 2021, the U.S. Food and Drug Administration (FDA) approved the first long-acting treatment for HIV. The once-a-month injection, administered by a healthcare provider, is a combination of cabotegravir and rilpivirine — sold under the brand name Cabenuva — and is meant for patients who have already lowered their viral load. The shots could be especially beneficial for people who struggle with a daily pill schedule.

Side Effects of Medication

All medicines have potential side effects, and HIV medicines are no different. When you first start ART, you may experience:
  • Anemia
  • Diarrhea
  • Headache
  • Fatigue
  • Nausea
  • Nerve problems
  • Rash
  • Pain
When taken long term, certain HIV medicines can be associated with serious side effects, such as high cholesterol, lipodystrophy (gain or loss of body fat), diabetes, osteoporosis, or liver damage. Ask your doctor what to expect and how to stay healthy.
According to the NIH’s Office of AIDS Research, ART is recommended for all transgender people with HIV, though some antiretroviral drugs may interact with gender-affirming hormone therapy. Be sure your doctor is aware of any other medications and supplements you’re taking and that they are monitoring you.

Prevention of HIV

There a number of strategies that can reduce your risk of becoming infected with HIV or greatly lower the odds that you will transmit the virus to an HIV-negative partner.

If you are using ART regularly and precisely as prescribed and have lowered your viral load to consistently undetectable levels (which usually takes up to six months, followed by ongoing care ) your risk of transmitting the virus to a sexual partner is essentially zero. Research shows this method of HIV prevention is 100 percent effective in preventing sexual transmission.

You can also reduce your risk of getting or transmitting HIV if you and your partner:

  • Use HIV prevention medications, an approach called pre-exposure prophylaxis (PrEP)
  • Take a combination of HIV medicines within 72 hours after you think you may have been exposed, an approach called post-exposure prophylaxis (PEP)
  • Use condoms correctly and consistently
  • Have a circumcised penis
  • Never share drug injection equipment
  • Limit your number of sexual partners
  • Abstain from sex or choose less-risky sexual behaviors, such as oral sex or mutual masturbation instead of anal or vaginal sex
  • Get checked and treated for other sexually transmitted diseases
HIV can be passed from mother to child at any point during pregnancy, but if you’re pregnant and have HIV, you can prevent this by making sure you take your HIV medicines as directed so that you have an undetectable viral load. By adhering to treatment throughout pregnancy, labor, and delivery, and if your baby takes HIV medicine four to six weeks after birth, you can lower the risk of transmission to 1 percent or less.

Complications of HIV

When HIV goes untreated, the virus itself can lead to twice the risk of heart disease, and increased neurological problems.

And that’s before HIV progresses to AIDS. Without treatment, the immune system’s CD4 cells become so damaged and destroyed that the body becomes susceptible to dangerous and fatal infections and certain cancers — specifically, lymphomas (cancers of the lymph nodes), Kaposi sarcoma (a blood vessel cancer), and invasive cervical cancer.
According to the CDC, if a person’s CD4 count falls below a certain level or a person develops one of these infections or cancers, they will be diagnosed with AIDS, the last stage of HIV. This usually happens after years of untreated HIV infection. You can reduce the chance you’ll be diagnosed with AIDS by taking antiretroviral therapy consistently and exactly as directed to reduce the amount of virus in your bloodstream.
People diagnosed with AIDS who are not on treatment are at high risk of becoming infected by a wide range of viruses and microbes, including bacteria, fungi, and parasites — these are called opportunistic infections (OIs) and include pneumonia and tuberculosis.
Usually, antiretroviral therapy restores the immune system and prevents OIs in people living with HIV. Still, some people aren’t diagnosed with HIV until they also qualify for an AIDS diagnosis. Or they may not be taking ART consistently, or their treatment isn’t keeping their viral load low enough for their immune system to do what it needs to.